Drought threatens to undermine agriculture across much of sub-Saharan Africa, John Holmes said. Battles over scarce resources may spur greater conflict, and if the Himalayan glaciers that supply much of Asia with water eventually

disappear, hundreds of millions of people may need to move, he added.

In an interview with AlertNet during the Copenhagen climate negotiations, Holmes, the U.N.'s chief of humanitarian affairs and emergency relief, outlined his concerns about climate change.

Q: What consequences of climate change worry you the most?

A: Immediately, it's storms -- typhoons and that sort of thing. But the most serious issue in the slightly longer term is drought. It's fundamental. If it's prolonged in places already

prone to drought it poses huge problems in how to deal with it. We have to ask after a while: are these places habitable?

Something like 94 percent of sub-Sahara's agriculture is rain fed. Half of that probably won't survive. And that's linked to the possibility of extra conflict being generated. Battles over resources may focus on energy or land, but water is the most obvious one.

State are good at reaching equitable water arrangements now. But will those arrangements survive with extra pressures? That's

an open question.

Q: Are there ways to help?

A: We'll have to do a massive amount to adapt to much more frequent drought. Right now the techniques for managing water better are there but there's not enough investment in them.

Q: What are your other big concerns?

A: Migration -- or forced displacement is a better word. It's going to be hard to distinguish who is an economic migrant and who is a climate refugee.

Moving people is one of the things we will need to do. If a new pattern of flooding arises and people live in places that flood over and over again, they will have to be moved. It's

happening as we speak in Ouagadougou (the capital of Burkina Faso), which now floods in a way it never did before.

Government is saying to people, 'We wonÂ?t allow you to go back and live in that low-lying area. We know it's going to happen again'. But that poses all sort of issues of how you achieve moving people, how you pay for relocation and other issues surrounding the human rights of people to stay. Can you insist on moving them? Governments are starting to face up to these problems.

Q: You said glacier melt, particularly in the Himalayas, is another huge concern, as is sea level rise.

A: Think about the Ganges delta in Bangladesh. It doesn't take much of a sea level rise for large parts of it to become uninhabitable. Tens of millions of people will have to go somewhere else. Bangladesh is full already. Where are they going to go?

It's not a problem for next year but it is perhaps in 20 years' time. We have to get arrangements in place, including legal conventions. Do we need to amend the 1951 convention on refugees? People are very nervous about that. Once you reopen that text, where is it going to lead? And are existing protection measures for internally displaced people sufficient? What is the effect going to be of that (high) level of migration?

If the Himalayan glaciers melt, that will have a major impact on Asia's rivers, where hundreds of millions of people live. That's a mega-scary scenario.

Q: How much are vulnerable countries themselves getting prepared to act on climate change?

A: For the last year I've been listening to disaster management people coming to my office from Gambia, Namibia, saying, "We never had floods here and now it's happening every

year and we don't know what to do". These problems don't show up on graphs of rainfalls because the averages look normal. But all

of a sudden the rain is coming all in one go.

People in these countries know climate change is not something for the future. It's here now, though of course it's going to get worse and will continue to get worse for the next 50 years ... no matter what we do on emissions (as a result of

the slow dissipation of greenhouse gases in the atmosphere).

Q: How much of a problem is it dealing with a gradual-onset problem like climate change?

A: We're set up to deal with natural disasters or conflict. Water scarcity and a whole raft of other problems will not trigger a single humanitarian crisis but chronic vulnerability.

Q: What's the key message you want to get across in Copenhagen?

A: This is not some future speculative thing. This is happening now and it is bound to get worse. And that climate change has a human face, and it is particularly that of the

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